1. Field of the Invention
The present invention relates to an aluminum nitride series ceramic having a high volume resistivity and a member for a system for producing semiconductors and a corrosion resistant member applying such a ceramic.
2. Related Art Statement
Aluminum nitride sintered bodies have a corrosion resistant property against a halogen has and have thus been utilized as a base material of various members for semiconductors producing systems. It is further needed that a base material for a ceramic heater has a specified insulating property and thermal conductivity in a specific operating temperature range. Aluminum nitride sintered bodies have an insulating property and a high thermal conductivity and thus have been utilized as a base material for ceramic heaters for heating silicon wafers. A dense aluminum nitride sintered body usually has a volume resistivity of about 1013Ω·cm at room temperature, for example, and not higher than 107Ω·cm at 500° C. An aluminum nitride sintered body having a volume resistivity of, for example, not lower than 108Ω·cm at 500° C., has thus been demanded.
The assignee filed Japanese patent publication 2000-44345A and disclosed a novel method of producing an aluminum nitride sintered body. In the disclosure, a magnesium component is added to raw material of aluminum nitride power to provide a sintered body having a high corrosion resistant property and volume resistivity.
Magnesium, however, is an alkaline earth metal element and has been considered to be not desirable in semiconductor production processes. In addition, it may be difficult to give a solution for a process carried out at a higher temperature range by the above method using a magnesium component.